Can scientists make moths gay?


Insect Pictures Can scientists make moths gay? Moth overpopulation in England led to a creative gender misdirection. Read and decide: can scientists make moths gay? See more insect pictures.

­During the summer of 2007, England's population of brown-tailed moths was getting out of control, particularly in Spurn Point, a nature reserve in the Yorkshire area. Warm spring temperatures, combined with ample food sources, ­had allowed the moths to flourish. British scientists were worried. A female brown-tailed moth lays 200 to 300 eggs, and the moths and their caterpillars can decimate an area's vegetation.

­The moth boom was also affecting local residents. Brown-tailed moth larvae have numerous little hairs that cause a person to develop an uncomfortable rash should the hairs come into contact with his skin. These hairs can also get into a person's lungs and create breathing problems. To stem the blossoming moth population, scientists devised an unusual plan: They made the male moths gay.

At least, that's what some commentators have called it. In actuality, the male moths were the targets of some deliberate misdirection. Scientists dispersed powdered female hormones near the moths' mating areas. Once moth larvae hatched, they became covered in the powder, and the male moths subsequently mistook the larvae for female moths and tried to mate with them.

­The ruse worked because of the power of the hormones and because the moths, to put it simply, are rather unintelligent. A scientist involved in the project said that the pheromones don't affect other types of moths or b­utterflies [Source: The Times].

Despite some headlines stating otherwise, the moths were not actually made homosexual. But the story led us to look at some interesting examples of how sexuality and gender can be quite fluid among animals.

Some animals can have their sex altered simply by the environment around them. Scientists once changed male embryos of bearded dragon lizards into females by increasing the temperature in their incubation chambers. The temperature increase overrode the chromosome that normally determines gender in these lizards. The research showed that sex isn't solely determined by one factor (chromosome or temperature) but rather can be a product of multiple factors. The scientists involved expressed excitement that the process of sex assignment was much more complex than they thought, but also voiced concern that a warming climate may create drastic gender inequalities among some species of animals, especially certain reptiles.

Numerous studies have shown that chemical pollution can drastically change the anatomy and reproductive capabilities of many animals. One study showed that polluting chemicals off of the coast of Britain caused many male clams to produce both sperm and eggs, a condition called intersexuality. Scientists worry that the clams' intersexuality could lead to reproductive problems and harm the local ecosystem or that animals that eat the clams will begin to show similar effects. The researchers named a few possible sources of the chemicals, including fertilizers, estrogen from sewage runoff and estrogen produced by cattle at nearby farms.

Similar instances of chemically induced intersex, feminization and masculization have been seen in polar bears, frogs, alligators, flounder and up to 200 other animals, all of whom, scientists believe, have been affected by endocrine active substances (EAS). EAS are chemicals that mimic hormones and can disrupt the body's natural hormones, leading to potentially damaging physical changes that can inhibit reproduction and create deformed offspring. Scientists and wildlife activists have voiced concerns that these substances, which can be natural hormones like estrogen or artificial chemicals, will drastically disrupt the populations of these animals and those that feed on them.

Despite these challenges, animals have shown a remarkable variety of sexual adaptations and behaviors. On the next page, we'll take a closer look at animal sexuality and learn how the animal world is more diverse than many people think.

Animal Sexuality

Photographer: Karin Van Ijzendoorn

­An October 2006 exhibition at the Oslo Natural History Museum in Oslo, Norway, focused on homosexuality among 51 animal species. The ­exhibition, which was the first of its kind, was devoted to showing that "homosexuality is a common and widespread phenomenon in the animal world" [Source: BBC News]. In fact, there are documented instances of homosexuality in 1,500 different animal species. A third of these species have been thoroughly studied. Some of these animals have lifelong same-sex partnerships.

In one article looking at the Oslo exhibition, an American anthropologist commented that the study of relationships among animals previously (and erroneously) focused on the idea that animals only mated to procreate and further the species [Source: MSNBC]. This assumption has been largely overturned. Not only do many animals participate in homosexual activity, but many animals -- of all sexual orientations -- engage in sex for pleasure.

In some groups, 10 percent of penguins are homosexual. It's estimated that more giraffes may be homosexual than heterosexual [Source: LiveScience]. Many male American bison engage in homosexual activity -- it's more common among them than heterosexual behavior. Female macaque monkeys participate in monogamous, homosexual relationships.

Besides representing a source of pleasure, these non-procreative sexual interactions often provide benefits to the animal community. Animals of the same sex sometimes make sexual "alliances" to protect a community or dominate an area. In some groups, an animal's homosexual encounters ensure its place of dominance or its chances of reproducing later. Bonobos, humans' closest animal relative, are bisexual and much of their sexual activity is done for pleasure rather than procreation. Scientists say that bonobos' homosexual behavior produces closer social bonds [Source: National Geographic].

In some bird species, a homosexual couple raises the young. It can happen in a few ways. A male couple might drive a female away from her eggs and then treat them as their own. Or, a male might fertilize a female's eggs, but a pair of females will raise them. Finally, a female sometimes enters a male couple's nest, mates with them, lays her eggs and leaves the males to tend to the eggs. Up to 25 percent of black swan pairings work like this [Source: MSNBC].

These and the many other documented examples show that sexuality and even gender are very fluid (or nonexistent) concepts among animals. Some scientists argue that sexuality and gender may in fact be nothing more than human constructs. Consider young male dolphins and walruses, which engage in homosexual relationships when they're young but become heterosexual once they reach adulthood. Other animals are hermaphrodites, possessing both male and female reproductive organs. Some can "switch" genders (a concept that was employed in the movie "Jurassic Park"). Many animals don't have sex. Some divide in order to reproduce. Others "clone" themselves. Some sea creatures leave it to chance, expelling their sperm or eggs where they mix with those from other animals and fertilize in the open ocean. The great variety of animal life in the world has produced an equally wide array of sexual habits, gender roles and methods of socializing, while much remains to be learned about how many animals live, love and reproduce.

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Sources

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